The impact of fetal gender and ethnicity on the risk of spontaneous preterm delivery in women with symptoms of preterm labor.

OBJECTIVE: The objective of this study is to evaluate the relation among fetal gender, ethnicity, and preterm labor (PTL) and preterm delivery (PTD). METHODS: A secondary analysis was performed of a prospective cohort study including women with symptoms of PTL between 24 and 34 weeks. The proportion of women carrying a male or female fetus at the onset of PTL was calculated. Gestational age at delivery and risk of PTD of both fetal genders was compared and interaction of fetal gender and maternal ethnicity on the risk of PTD was evaluated. RESULTS: Of the 594 included women, 327 (55%) carried a male fetus. Median gestational age at delivery in women pregnant with a male fetus was 37 5/7 (IQR 34 4/7-39 1/7) weeks compared with 38 1/7 (IQR 36 0/7-39 5/7) weeks in women pregnant with a female fetus (p = 0.032). The risk of PTD did not differ significantly. In Caucasians, we did find an increased risk of PTD before 37 weeks in women pregnant with a male fetus (OR 1.9 (95% CI 1.2-3.0)). CONCLUSIONS: The majority of women with PTL are pregnant with a male fetus and these women deliver slightly earlier. Race seems to affect this disparity.

Risk factors for preterm delivery: do they add to fetal fibronectin testing and cervical length measurement in the prediction of preterm delivery in symptomatic women?

OBJECTIVE: To assess whether patient characteristics add to the fetal fibronectin test and cervical length measurement in the prediction of preterm delivery in symptomatic women. STUDY DESIGN: A nationwide prospective cohort study was conducted in all ten perinatal centres in the Netherlands. Women with symptoms of preterm labour between 24 and 34 weeks gestation with intact membranes were invited. In all women qualitative fibronectin testing (0.050 µg/mL cut-off) and cervical length measurement were performed. Only singleton pregnancies were included in this analysis. Logistic regression was used to construct two multivariable models to predict spontaneously delivery within 7 days: a model including cervical length and fetal fibronectin as predictors, and an extended model including all potential predictors. The models were internally validated using bootstrapping techniques. Predictive performances were assessed as the area under the receiver operator characteristic curve (AUC) and calibration plots. We compared the models' capability to identify women with a low risk to deliver within 7 days. A risk less than 5%, corresponding to the risk for women with a cervical length of at least 25 mm, was considered as low risk. RESULTS: Seventy-three of 600 included women (12%) had delivered spontaneously within 7 days. The extended model included maternal age, parity, previous preterm delivery, vaginal bleeding, C-reactive protein, cervical length, dilatation and fibronectin status. Both models had high discriminative performances (AUC of 0.92 (95% CI 0.88-0.95) and 0.95 (95% CI 0.92-0.97) respectively). Compared to the model with fibronectin and cervical length, our extended model reclassified 38 women (6%) from low risk to high risk and 21 women (4%) from high risk to low risk. Preterm delivery within 7 days occurred once in both the reclassification groups. CONCLUSION: In women with symptoms of preterm labour before 34 weeks gestation, a model that integrates maternal characteristics, clinical signs and laboratory tests, did not predict delivery within 7 days better than a model with only fibronectin and cervical length.

Risk stratification with cervical length and fetal fibronectin in women with threatened preterm labor before 34 weeks and not delivering within 7 days.

OBJECTIVE: To stratify the risk of spontaneous preterm delivery using cervical length (CL) and fetal fibronectin (fFN) in women with threatened preterm labor who remained pregnant after 7 days. DESIGN: Prospective observational study. SETTING: Nationwide cohort of women with threatened preterm labor from the Netherlands. POPULATION: Women with threatened preterm labor between 24 and 34 weeks with a valid CL and fFN measurement and remaining pregnant 7 days after admission. METHODS: Kaplan-Meier and Cox proportional hazards models were used to estimate cumulative percentages and hazard ratios (HR) for spontaneous delivery. MAIN OUTCOME MEASURES: Spontaneous delivery between 7 and 14 days after initial presentation and spontaneous preterm delivery before 34 weeks. RESULTS: The risk of delivery between 7 and 14 days was significantly increased for women with a CL < 15 mm or a CL ≥15 to <30 mm and a positive fFN, compared with women with a CL ≥30 mm: HR 22.3 [95% confidence interval (CI) 2.6-191] and 14 (95% CI 1.8-118), respectively. For spontaneous preterm delivery before 34 weeks the risk was increased for women with a CL < 15 mm [HR 6.3 (95% CI 2.6-15)] or with a CL ≥15 to <30 mm with either positive fFN [HR 3.6 (95% CI 1.5-8.7)] or negative fFN [HR 3.0 (95% CI 1.2-7.1)] compared with women with a CL ≥ 30 mm. CONCLUSIONS: In women remaining pregnant 7 days after threatened preterm labor, CL and fFN results can be used in risk stratification for spontaneous delivery.

Predictive value of cervical length measurement and fibronectin testing in threatened preterm labor.

OBJECTIVE: To estimate the performance of combining cervical length measurement with fetal fibronectin testing in predicting delivery in women with symptoms of preterm labor. METHODS: We conducted a prospective nationwide cohort study in all 10 perinatal centers in The Netherlands. Women with symptoms of preterm labor between 24 and 34 weeks of gestation with intact membranes were included. In all women, qualitative fibronectin testing (0.050-microgram/mL cutoff) and cervical length measurement were performed. Logistic regression was used to predict spontaneous preterm delivery within 7 days after testing. A risk less than 5%, corresponding to the risk for women with a cervical length of at least 25 mm, was considered as low risk. RESULTS: Between December 2009 and August 2012, 714 women were enrolled. Fibronectin results and cervical length were available for 665 women, of whom 80 (12%) delivered within 7 days. Women with a cervical length of at least 30 mm or with a cervical length between 15 and 30 mm with a negative fibronectin result were at low risk (less than 5%) of spontaneous delivery within 7 days. Fibronectin testing in case of a cervical length between 15 and 30 mm additionally classified 103 women (15% of the cohort) as low risk and 36 women (5% of the cohort) as high risk. CONCLUSION: Cervical length measurement, combined with fetal fibronectin testing in case of a cervical length between 15 and 30 mm, improves identification of women with a low risk to deliver spontaneously within 7 days. LEVEL OF EVIDENCE: II.

Induction of labour versus expectant monitoring for gestational hypertension or mild pre-eclampsia between 34 and 37 weeks' gestation (HYPITAT-II): a multicentre, open-label randomised controlled trial.

BACKGROUND: Gestational hypertension (GH) and pre-eclampsia (PE) can result in severe complications such as eclampsia, placental abruption, syndrome of Hemolysis, Elevated Liver enzymes and Low Platelets (HELLP) and ultimately even neonatal or maternal death. We recently showed that in women with GH or mild PE at term induction of labour reduces both high risk situations for mothers as well as the caesarean section rate. In view of this knowledge, one can raise the question whether women with severe hypertension, pre-eclampsia or deterioration chronic hypertension between 34 and 37 weeks of gestation should be delivered or monitored expectantly. Induction of labour might prevent maternal complications. However, induction of labour in late pre-term pregnancy might increase neonatal morbidity and mortality compared with delivery at term. METHODS/DESIGN: Pregnant women with severe gestational hypertension, mild pre-eclampsia or deteriorating chronic hypertension at a gestational age between 34+0 and 36+6 weeks will be asked to participate in a multi-centre randomised controlled trial. Women will be randomised to either induction of labour or expectant monitoring. In the expectant monitoring arm, women will be induced only when the maternal or fetal condition detoriates or at 37+0 weeks of gestation. The primary outcome measure is a composite endpoint of maternal mortality, severe maternal complications (eclampsia, HELLP syndrome, pulmonary oedema and thromboembolic disease) and progression to severe pre-eclampsia. Secondary outcomes measures are respiratory distress syndrome (RDS), neonatal morbidity and mortality, caesarean section and vaginal instrumental delivery rates, maternal quality of life and costs. Analysis will be intention to treat. The power calculation is based on an expectant reduction of the maternal composite endpoint from 5% to 1% for an expected increase in neonatal RDS from 1% at 37 weeks to 10% at 34 weeks. This implies that 680 women have to be randomised. DISCUSSION: This trial will provide insight as to whether in women with hypertensive disorders late pre-term, induction of labour is an effective treatment to prevent severe maternal complications without compromising the neonatal morbidity. TRIAL REGISTRATION: NTR1792 CLINICAL TRIAL REGISTRATION: http://www.trialregister.nl.